Copy edit new addition

Amanda Butler · web-flow · commit 1fbbf57a7f9a · 2017-09-12T11:15:17.000-05:00
Delete unnecessary word, and change mood for consistent mood/tense and voice.
diff --git a/docs/contributing/systick_tickless.md b/docs/contributing/systick_tickless.md
@@ -23,4 +23,4 @@ Targets supporting tickless mode override the default SysTick mechanism and use
 
 ### Testing
 
-Currently there are no dedicated tests validating tickless mode. Running all Mbed OS tests suits, with particular focus on HAL sleep and HAL low power ticker tests, should provide sufficient coverage.
+There are no dedicated tests validating tickless mode. Running all Mbed OS tests suits, with particular focus on HAL sleep and HAL low power ticker tests, provides sufficient coverage.

Original file line number	Diff line number	Diff line change
`@@ -23,4 +23,4 @@ Targets supporting tickless mode override the default SysTick mechanism and use`
`23`	`23`
`24`	`24`	`### Testing`
`25`	`25`
`26`		`-Currently there are no dedicated tests validating tickless mode. Running all Mbed OS tests suits, with particular focus on HAL sleep and HAL low power ticker tests, should provide sufficient coverage.`
	`26`	`+There are no dedicated tests validating tickless mode. Running all Mbed OS tests suits, with particular focus on HAL sleep and HAL low power ticker tests, provides sufficient coverage.`